The present invention relates to a polyurea coating composition that can be applied as a wet finish on any substrate. More particularly, the present invention relates to a two component polyurea coating composition that exhibits a dual cure phenomena.
Two component coating compositions containing a polyisocyanate component in combination with an isocyanate-reactive such as a polyhydroxyl component or a polyamine are known. These coating compositions are suitable for the formation of high quality coatings and can be adjusted to produce coatings which are hard, elastic, abrasion resistant, solvent resistant and weather resistant.
Generally, there are two mechanisms by which the curing of polyurea coating compositions takes placexe2x80x94moisture cure or plural component xe2x80x9cfast curexe2x80x9d which involves cross-linking the polyisocyanate component with an amine. Aliphatic coating compositions which rely upon moisture cure demonstrate very slow curing times which can limit their use in some applications. Coating compositions which rely upon plural xe2x80x9cfast curexe2x80x9d are susceptible to adhesion problems when the curing proceeds too quickly.
In accordance with the present invention, polyurea coating compositions based on a two component system of a polyisocyanate component and a polyaspartic ester isocyanate-reactive component are produced which demonstrate a dual cure phenomena which results in improved film properties and curing times.
According to other features, characteristics, embodiments and alternatives of the present invention which will become apparent as the description thereof proceeds below, the present invention provides a polyurea coating composition that exhibits a dual cure phenomena, the polyurea coating composition including:
a polyaspartic ester; and
a polyisocyanate,
wherein the polyisocyanate is present in an amount that is greater than a normal stoichiometric amount for the polyaspartic ester.
The present invention further provides a method of preparing a polyurea coating composition which involves:
providing a polyaspartic ester;
providing a polyisocyanate; and
mixing the polyaspartic ester and the polyisocyanate together so that the polyisocyanate is present in an amount that is greater than a normal stoichiometric amount for the polyaspartic ester.
The present invention also provides a surface finish which comprises a cured composition that includes a polyaspartic ester and a polyisocyanate, wherein the polyisocyanate is present in an amount that is greater than a normal stoichiometric amount for the polyaspartic ester prior to curing.
The present invention still further provides a method for forming a surface finish which involves:
providing a polyaspartic ester;
providing a polyisocyanate;
mixing the polyaspartic ester and the polyisocyanate together so that the polyisocyanate is present in an amount that is greater than a normal stoichiometric amount for the polyaspartic ester;
applying the mixed composition to a surface to form a surface coating; and
allowing the applied surface coating to cure.